UNDER-WATER WARFARE
The submarine is supposed to have its most important field of operation against a fleet of battleships and cruisers besieging a seaport city. These great war craft, covered above the waterline with thick steel armor, are vulnerable below, and a torpedo discharged from a torpedo boat or an explosive bomb attached to the lower hull by a submarine may send the largest and mightiest ship to the bottom, stung to death from below.
With this idea in view torpedo boars, destroyers designed to attack torpedo boats and submarines have been multiplied in modern navies. We have just begun to appreciate the effectiveness of this type of vessels. Their possibilities are enormous and their latent power renders the bombardment from sea of town or fort a far more perilous operation than of old. Fired at by the great guns of the fort capable of effective work at eight or ten miles distance, exposed to explosive bombs dropped from soaring airships, made a target for the deadly weapon of the torpedo boat, and in constant risk of being stung by the submarine wasp, these great war ships, built at a cost of ten or more millions and peopled by hundreds of mariners, are in constant danger of being sent to the bottom with all on board a contingency likely to shake the nerves of the steadiest Jack Tar or admiral on board.
A typical submarine has a length of about 150 feet and diameter of 15 feet, with a speed of eleven knots on the surface and five knots when submerged. Some of the more recent have a radius of navigation of 4,500 miles without need of a new supply of stores and fuel. On the surface they are propelled by gasoline engines, but when submerged they use electric motors driven by storage batteries. If the weather should grow too rough they can sink below the waves.